1. Field of the Invention
This invention relates in general to electronic assemblies, and, in particular, to a two switch, wide range converter.
2. Description of Related Art
DC voltage to DC voltage converters (DC-to-DC) have found many applications in electronic assemblies. One example of a DC-to-DC converter is a converter known as a xe2x80x9cVenablexe2x80x9d converter, which is disclosed in U.S. Pat. No. 3,925,715. The Venable converter requires four switching devices or transistors, a diode, an inductor, and a high voltage transformer.
Other DC-to-DC converter circuits are also known. One example is disclosed in U.S. Pat. No. 4,943,903, which is incorporated by reference herein. The Cardwell converter requires 4 switches, one inductor, an adder transformer, and a high voltage transformer.
Since each component used in the DC-DC converter can represent a single point of failure, all other things equal, the reliability of the DC-DC converter goes down as the component or part count of the converter goes up. Increased part count also typically results in greater mass. Reliable operation is critical in many applications, including spacecraft applications. Further, additional parts increase the weight of such spacecraft, which increases the costs of the satellite in terms of launch costs, testing, and certification of all of the parts in the converter assembly.
There is therefore a need in the art for a DC-to-DC converter that requires fewer parts than the converters of the related art. There is also a need in the art for a DC-to-DC converter that has a reduced weight compared to that of the related art. There is also a need in the art for a DC-to-DC converter that can operate over a very large change in the converter input voltage.
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a power converter and a method for converting power. The power converter comprises an inductor, a transformer, first and second switches, a diode, and a full bridge. The inductor comprises a first winding, a second winding, and a third winding, and is coupled to an input voltage. The transformer has a first primary winding coupled to the first winding of the inductor, a second primary winding coupled to the second winding of the inductor, and a third primary winding coupled to the third winding of the inductor. The first switch is coupled to the first primary winding of the transformer, and the second switch is coupled to the second primary winding of the transformer. The diode is coupled to the third primary winding of the transformer. The full bridge is coupled to a secondary winding of the transformer, and the output voltage emanates therefrom.
A method in accordance with the present invention comprises the steps of switching a first switch that is series coupled to a first primary winding of a transformer and a first winding of an inductor, switching a second switch that is series coupled to a second primary winding of the transformer and a second winding of the inductor, coupling a diode to a third primary winding of the transformer and a third winding of the inductor, and coupling a full bridge to a secondary winding of the transformer, wherein the transformer, inductor, first switch, second switch, diode, and full bridge convert the input voltage coupled to the inductor to an output voltage emanating from the full bridge.
The present invention provides a DC-to-DC converter that requires fewer parts than the converters of the related art. The present invention also provides a DC-to-DC converter that has a reduced weight compared to that of the related art. The present invention also provides a DC-to-DC converter can operate over a very wide variation in the input voltage. For example, the present invention can operate with input voltage variations of 4:1. This would allow the converter to provide a fully regulated output with an input voltage variation from 25 VDC to 100 VDC. Theoretically, the input voltage variation can be much greater, but practical limitations due to component voltage ratings may ultimately limit the maximum input voltage range.